Uncommanded Parking Brake activation after a stop?

[apMechorse]

This issue has been a problem since I first picked up my truck.

Background: Truck specs are listed below, I normally leave Auto-Hold brakes turned ON.

Issue: Rarely, but with increasing frequency, after coming to a complete stop (Auto-Hold brakes engaged) I will tap the throttle to disengage the Auto-Hold and will start to roll forward. Just as I press the throttle to pick up speed (<3-5 mph) the Parking Brake will engage bringing the truck to a very abrupt and violent stop. The Parking Brake engaged message comes on, and the red BRAKE message stays on. The Parking Brake will disengage automatically as per normal once the throttle is tapped again.

This issue only happens on average once every ~100-200 stops, but can sometimes happen multiple times in a row. It has happened on level pavement and on an incline. It's happened at the entrance to our parking ramp, at stop signs and at stop lights... this last one has almost resulted in being rear-ended on more than on occasion.

It has no error messages, and leaves no trace that anything is amiss. And of course it can't be reproduced intentionally. The service dept probably thinks I'm making it up at this point because apparently no one else nation-wide has reported anything like this, and it's been on my laundry list every time I've brought my truck in for any kind of service.

Of all the issues I've had with this truck since new, this is the only one that I would say is a certified safety issue.

Has anyone else ever had this happen to them? If so have you found a way to reproduce it, or even better a solution for it? Thanks.

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[Ford Motor Company]

This issue has been a problem since I first picked up my truck.

Background: Truck specs are listed below, I normally leave Auto-Hold brakes turned ON.

Issue: Rarely, but with increasing frequency, after coming to a complete stop (Auto-Hold brakes engaged) I will tap the throttle to disengage the Auto-Hold and will start to roll forward. Just as I press the throttle to pick up speed (<3-5 mph) the Parking Brake will engage bringing the truck to a very abrupt and violent stop. The Parking Brake engaged message comes on, and the red BRAKE message stays on. The Parking Brake will disengage automatically as per normal once the throttle is tapped again.

This issue only happens on average once every ~100-200 stops, but can sometimes happen multiple times in a row. It has happened on level pavement and on an incline. It's happened at the entrance to our parking ramp, at stop signs and at stop lights... this last one has almost resulted in being rear-ended on more than on occasion.

It has no error messages, and leaves no trace that anything is amiss. And of course it can't be reproduced intentionally. The service dept probably thinks I'm making it up at this point because apparently no one else nation-wide has reported anything like this, and it's been on my laundry list every time I've brought my truck in for any kind of service.

Of all the issues I've had with this truck since new, this is the only one that I would say is a certified safety issue.

Has anyone else ever had this happen to them? If so have you found a way to reproduce it, or even better a solution for it? Thanks.

Hello, Steve! Send us a private message with your VIN and the name and location of your local Ford dealer. I’d be happy to see what I can do to assist with this concern. Thanks!

 

[Snakebitten]

Just asking because although I do NOT enable auto-Hold, but rather use the steering wheel controls to initiate a brake-hold at a traffic stop, I have experienced the emergency brake being engaged if a brake-hold request results in a long enough hold time.

In other words, if the truck is being brake-held by the PCM, rather than my foot on the brake pedal, after a certain elapsed time the truck will apply the electric parking brake and notify me on the instrument cluster.

Do you think that "elapsed time" might be a participant in your scenario?

 

[Oxford_Powerboost]

Just asking because although I do NOT enable auto-Hold, but rather use the steering wheel controls to initiate a brake-hold at a traffic stop, I have experienced the emergency brake being engaged if a brake-hold request results in a long enough hold time.

In other words, if the truck is being brake-held by the PCM, rather than my foot on the brake pedal, after a certain elapsed time the truck will apply the electric parking brake and notify me on the instrument cluster.

Do you think that "elapsed time" might be a participant in your scenario?

I use autohold all the time - in fact I don’t think it’s been switched off since I left Chapman Ford 29k miles ago. I’ve never sat long enough for the park brake to auto apply - my understanding is that the time limit is around 30 minutes.

I frequently find myself sitting in drive in parking lots waiting for someone for extended periods in auto hold as I learned (by inspiration from you) that the HV draw is the same in drive with auto hold enabled as it is in park. So there is no efficiency benefit to sitting in park vs drive. Yet, I’ve never had it auto apply the parking brake. I try to use park, but it’s a bit of a forgetful habit

OP - if you have access to Forscan, I’d love to see if your truck is throwing any codes for this. I’m wondering if it’s a brake booster issue or something of the like

 

[Snakebitten]

I experience it at trains.

Which in my small town is not an unusual thing to encounter.
I never considered it a fault or a sign of an issue. It does take a few minutes before it will switch from the PCM-hold to the E-brake hold, but it's far less than 30 minutes.

Since I do not have auto-Hold enabled, maybe there's different code written that applies to driver commanded hold? (It's initiated by coming to a stop behind another vehicle and then using the steering wheel cruise control button to trigger adaptive cruise. Since you are at a stop, it sets cruise control to 15mph. And after a few seconds, the instrument panel notifies you that you are "stopped" and that you must hit the resume button for the vehicle to release the brakes for you. At that point I take my foot off the brake and the PCM is commanding the ABS module to hold the vehicles brakes. At a lengthy hold, like a train crossing, it eventually hands off the brake hold to the E-brake and again notifies the driver)

I love this truck!

 

[Wallyo]

Went out tonight for a drive, was heading down a lane that had a fairly steep dive to the Main Street. Once you hit the street an up hill climb until you were over the center hump of the main steet. This was in a hillside neighborhood and is designed this way for drainage.

I stopped at the top to be sure no one was turning in as the lane is about 1 1/2 cars wide. press the gas, not moving, Parking break light on. Ok turn. it off. Proceed down to the stop sign midway again!
Felt like I was bottomed out. Went around to the lane entrance down again, a third time brake decided to engage!

Get home and recall is in todays mail. It states "they should come into the dealership, who can do an interim repair"

So is my problem recall related of more Like the above; I was able to repeat it.

 

[Bo15]

Went out tonight for a drive, was heading down a lane that had a fairly steep dive to the Main Street. Once you hit the street an up hill climb until you were over the center hump of the main steet. This was in a hillside neighborhood and is designed this way for drainage.

I stopped at the top to be sure no one was turning in as the lane is about 1 1/2 cars wide. press the gas, not moving, Parking break light on. Ok turn. it off. Proceed down to the stop sign midway again!
Felt like I was bottomed out. Went around to the lane entrance down again, a third time brake decided to engage!

Get home and recall is in todays mail. It states "they should come into the dealership, who can do an interim repair"

So is my problem recall related of more Like the above; I was able to repeat it.

Good question. I’ve experienced the same once w autohold enabled and going down a steep section to a stop sign.

 

[Wallyo]

I made an appointment for Thursday for them to look at it. I am going back up there this weekend to see if it happens again and will video it so I don’t get the.
“Well the tech drove it for 15 minutes and it didn’t happen to him”

The indicator light is in the lower right corner when it happens it is surprising and you at first don’t know it happens because your eye is not drawn to the light. Hopefully this only happens on a stopped vehicle and not one doing 85 on. i 84!

 

[Wallyo]

Went into the dealership today. And of course what i thought would happen did happen. They checked it over was not the recalled harness. Do not Know how hard they tried but they could of course not replicate it, though I was able to!

I am worried that i might be going down a mountain pass and having it happen and not be able to release it in time and getting rear ended. Or releasing it proceeding and having it re-activate and getting rear ended.

So next step is a you tube video post it for the world to see., good thing I don't live of the street it happened on it get old real fast.

Ford are you listening?

I guess a complaint to the Feds as well!

 

[Wallyo]

I recreated it again 3 times today.
In the video when then parking brake self activates I am in drive, both hands on steering wheel, foot is off the brake and on the gas. You can hear the truck skid to a stop notice the brake light goes on .
Still photo showing the slope. Since my daughter dropped her bronco off at the dealer I again talked with the service manager nothing they can do for now.


The reference in the end is referring to how close we got it to recreate like the first time! We had made about 6 passes parking brake set itself on 3 out of the six but this was the most sudden and moving the fastest.

 

[Grafx36510]

I’ve had this happen once. I was on a steepish slope and I was slowing down to a stop sign at an intersection. And just like the video, I stepped on the gas and the truck applied the parking brake and I heard the skid of the rear tires. I may have caught it on my dashcam (only because the other driver at the intersection flipped me off and my son is quick on the save recording feature), but I’ll have to go back and check to see for sure. It was a definite, “that was weird” moment.

 

[Wallyo]

Hello, Steve! Send us a private message with your VIN and the name and location of your local Ford dealer. I’d be happy to see what I can do to assist with this concern. Thanks!

Hi this has happened to 5 trucks just on this thread, including myself. I live in a mountainous region and am very concerned about the safety at this point. The dealer has been unable to find any issue or code at this point. Could we get some assistance?

Above, I have attached a video of the issue, if you could review it.

 

[fordtruckman2003]

Hi this has happened to 5 trucks just on this thread, including myself. I live in a mountainous region and am very concerned about the safety at this point. The dealer has been unable to find any issue or code at this point. Could we get some assistance?

Above, I have attached a video of the issue, if you could review it.

You'll have more luck calling Ford and talking to someone reading the script over phone.

Definitely a concern if truck is randomly braking while accelerator is pressed. I can see if applying brake on a steep slope when not moving but to do while you are trying to drive is a bit scary.

 

[Wallyo]

You'll have more luck calling Ford and talking to someone reading the script over phone.

Definitely a concern if truck is randomly braking while accelerator is pressed. I can see if applying brake on a steep slope when not moving but to do while you are trying to drive is a bit scary.

Even the Service manager saw the video he was unwilling to call Ford. He Said "we probably know more about the trucks than they do"!

 

[fordtruckman2003]

I will say every time I manually activate parking brake it releases itself when I hit the accelerator. Seems yours isn't doing that?

Don't be afraid to try a different dealer. They all get the same crappy pay for warranty work. Some are more willing to help than others in the interest of earning future business.

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